/*
 * Copyright (C) 2015 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#ifndef LIBZIPARCHIVE_ZIPWRITER_H_
#define LIBZIPARCHIVE_ZIPWRITER_H_

#include <cstdio>
#include <ctime>

#include <memory>
#include <string>
#include <vector>

#include "android-base/macros.h"
#include "utils/Compat.h"

struct z_stream_s;
typedef struct z_stream_s z_stream;

/**
 * Writes a Zip file via a stateful interface.
 *
 * Example:
 *
 *   FILE* file = fopen("path/to/zip.zip", "wb");
 *
 *   ZipWriter writer(file);
 *
 *   writer.StartEntry("test.txt", ZipWriter::kCompress | ZipWriter::kAlign);
 *   writer.WriteBytes(buffer, bufferLen);
 *   writer.WriteBytes(buffer2, bufferLen2);
 *   writer.FinishEntry();
 *
 *   writer.StartEntry("empty.txt", 0);
 *   writer.FinishEntry();
 *
 *   writer.Finish();
 *
 *   fclose(file);
 */
class ZipWriter {
public:
    enum {
        /**
         * Flag to compress the zip entry using deflate.
         */
        kCompress = 0x01,

        /**
         * Flag to align the zip entry data on a 32bit boundary. Useful for
         * mmapping the data at runtime.
         */
        kAlign32 = 0x02,
    };

    /**
     * A struct representing a zip file entry.
     */
    struct FileEntry {
        std::string path;
        uint16_t compression_method;
        uint32_t crc32;
        uint32_t compressed_size;
        uint32_t uncompressed_size;
        uint16_t last_mod_time;
        uint16_t last_mod_date;
        uint32_t padding_length;
        off64_t local_file_header_offset;
    };

    static const char* ErrorCodeString(int32_t error_code);

    /**
     * Create a ZipWriter that will write into a FILE stream. The file should be opened with
     * open mode of "wb" or "w+b". ZipWriter does not take ownership of the file stream. The
     * caller is responsible for closing the file.
     */
    explicit ZipWriter(FILE* f);

    // Move constructor.
    ZipWriter(ZipWriter&& zipWriter);

    // Move assignment.
    ZipWriter& operator=(ZipWriter&& zipWriter);

    /**
     * Starts a new zip entry with the given path and flags.
     * Flags can be a bitwise OR of ZipWriter::kCompress and ZipWriter::kAlign.
     * Subsequent calls to WriteBytes(const void*, size_t) will add data to this entry.
     * Returns 0 on success, and an error value < 0 on failure.
     */
    int32_t StartEntry(const char* path, size_t flags);

    /**
     * Starts a new zip entry with the given path and flags, where the
     * entry will be aligned to the given alignment.
     * Flags can only be ZipWriter::kCompress. Using the flag ZipWriter::kAlign32
     * will result in an error.
     * Subsequent calls to WriteBytes(const void*, size_t) will add data to this entry.
     * Returns 0 on success, and an error value < 0 on failure.
     */
    int32_t StartAlignedEntry(const char* path, size_t flags, uint32_t alignment);

    /**
     * Same as StartEntry(const char*, size_t), but sets a last modified time for the entry.
     */
    int32_t StartEntryWithTime(const char* path, size_t flags, time_t time);

    /**
     * Same as StartAlignedEntry(const char*, size_t), but sets a last modified time for the entry.
     */
    int32_t StartAlignedEntryWithTime(const char* path, size_t flags, time_t time, uint32_t alignment);

    /**
     * Writes bytes to the zip file for the previously started zip entry.
     * Returns 0 on success, and an error value < 0 on failure.
     */
    int32_t WriteBytes(const void* data, size_t len);

    /**
     * Finish a zip entry started with StartEntry(const char*, size_t) or
     * StartEntryWithTime(const char*, size_t, time_t). This must be called before
     * any new zip entries are started, or before Finish() is called.
     * Returns 0 on success, and an error value < 0 on failure.
     */
    int32_t FinishEntry();

    /**
     * Discards the last-written entry. Can only be called after an entry has been written using
     * FinishEntry().
     * Returns 0 on success, and an error value < 0 on failure.
     */
    int32_t DiscardLastEntry();

    /**
     * Sets `out_entry` to the last entry written after a call to FinishEntry().
     * Returns 0 on success, and an error value < 0 if no entries have been written.
     */
    int32_t GetLastEntry(FileEntry* out_entry);

    /**
     * Writes the Central Directory Headers and flushes the zip file stream.
     * Returns 0 on success, and an error value < 0 on failure.
     */
    int32_t Finish();

private:
    DISALLOW_COPY_AND_ASSIGN(ZipWriter);

    int32_t HandleError(int32_t error_code);
    int32_t PrepareDeflate();
    int32_t StoreBytes(FileEntry* file, const void* data, size_t len);
    int32_t CompressBytes(FileEntry* file, const void* data, size_t len);
    int32_t FlushCompressedBytes(FileEntry* file);

    enum class State {
        kWritingZip,
        kWritingEntry,
        kDone,
        kError,
    };

    FILE* file_;
    bool seekable_;
    off64_t current_offset_;
    State state_;
    std::vector<FileEntry> files_;
    FileEntry current_file_entry_;

    std::unique_ptr<z_stream, void (*)(z_stream*)> z_stream_;
    std::vector<uint8_t> buffer_;
};

#endif /* LIBZIPARCHIVE_ZIPWRITER_H_ */
